Question

Ratio of $s{{p}^{3}}$ and $s{{p}^{2}}$ hybridized atoms in the anionic part of the borax is: (if answer is 12:4, then represent as 124)
(a)- 0101
(b)- 1201
(c)- 1121
(d)- 1321

Answer 1

Hint: The formula of borax is $N{{a}_{2}}[{{B}_{4}}{{O}_{5}}{{(OH)}_{4}}].8{{H}_{2}}O$, but in simplified form it is written as $N{{a}_{2}}{{B}_{4}}{{O}_{7}}.10{{H}_{2}}O$. So the anionic part of borax has formula ${{[{{B}_{4}}{{O}_{5}}{{(OH)}_{4}}]}^{2-}}$. The hybridization can be calculated by the structure of the specific boron atom.

Complete answer:
Borax is a compound of boron element of group 13 in which sodium is also present. The formula of borax is $N{{a}_{2}}[{{B}_{4}}{{O}_{5}}{{(OH)}_{4}}].8{{H}_{2}}O$, but in simplified form it is written as $N{{a}_{2}}{{B}_{4}}{{O}_{7}}.10{{H}_{2}}O$. So the anionic part of borax has formula ${{[{{B}_{4}}{{O}_{5}}{{(OH)}_{4}}]}^{2-}}$. It is a very important compound that is used for the preparation of tiles, pottery, etc.
Actually, the structure of the anionic form of borax contains tetranuclear units. So in the structure, two boron atoms have a negative charge and two boron atoms are neutral, each boron atom has one hydroxyl group and all the boron atoms are joined together with oxygen bonds. The structure is given below:

Sometimes, we cannot predict the hybridization of the atom by the number of bonds, so we have to see the geometry of the atom. So in the anionic part of borax, the two boron atoms that have negative charge have tetrahedral geometry and the two neutral boron atoms have trigonal planar geometry. And we know that the tetrahedral geometry have $s{{p}^{3}}$hybridization and trigonal planar have $s{{p}^{2}}$hybridization.
So their ratio is 2:2, which can be simplified as 1:1.

Therefore, the correct answer is option (a)- 0101.

Note:
If the geometry is linear, then the hybridization is $sp$. Borax has antiseptic property so it is used in medicinal soaps and laboratories and it is used for borax bead test.